Hi Bengt and Linda. I have an question for you about creating a measurement model based on one single composite latent varialbe. We had oringially hpothesized that all the indicators would go into the latent varialbe(success)instead of coming out of the latent construct.We have been reading about formative vs. reflective models and we had theorized a formative model. I also thought that I had specified a formative model, but what it is saying in papers is that the model wouldn't be identified unless there were refletive items going out of the success construct or other latent constructs coming out of the success construct. In the model that I specified, it was identifed and I had one measure set to 1.0 with measurement erro set to 0 and now I'm worried that it's not specified as a formative model. Is there a way to do a formative model in mplus using the by statements or does it automatically do a reflective model with by statements?

"In some applications it may be more natural to let a factor be defined as being influenced by indicators, rather than influencing the indicators. An example is SES. Mplus handles this modeling by the following model statements.

Hi Linda. Thank you for your response. Is the y an overall measure of the f and the x's the rest of the indicators that we think goes into the f? Can there only be one y? Could you give me an example with say SES in terms of what the y is and what the x's are? Thank you! Amanda

y is just an example of a variable that you want to predict using f. It can be a factor measured by several indicators. For example, the x's may be education, SEI, and income, and y may be achievement.